This invention relates to roll baling machines which form cylindrical rolls of crop material and which are commonly referred to as round balers.
In U.S. Pat. No. 4,566,379, there is disclosed a round baler having two sets of bale-forming means which define a bale-forming chamber which is expandable from a small start chamber to a full size chamber. In order to provide the expandable bale-forming chamber, one set of bale-forming means is movable with respect to the other set but it has been found that with some crops and/or crop conditions, this is insufficient to ensure that the core of a bale being formed is properly constituted and that the bale is continually rotated during formation. It is highly desirable that the core of a bale being formed has the correct density. It is furthermore essential to ensure that a bale being formed undergoes continual rotation in order that crop material being fed into the machine is taken in and added to the bale. If bale rotation ceases, then further crop material cannot be added to the bale which thus results in the baler becoming blocked.
In co-pending U.S. patent application Ser. No. 111,379, filed Oct. 20, 1987, there is disclosed a round baler which overcomes the shortcomings of this known machine while taking advantage of the basically satisfactory general type of bale-forming means employed therein. More specifically, this copending patent application discloses a baler in which the bale-forming means which is movable relative to the other bale-forming means itself also has at least two portions which are movable relative to each other. This provides a better shape of the bale start chamber (as seen in end view). This feature provides very satisfactory results in that a bale of a required density can be formed and the bale being formed is continually rotated thus preventing any blockage of the machine.
However, it has been found that, in order to allow the one bale-forming means to move relative the other one which is fixed, (the two means eventually cooperate to define the full size bale chamber) the adjacent ends of these means have to be spaced from each other in the full bale size position by an amount which permits this relative movement without the adjacent ends fouling each other. This spacing is not optimum as regards preventing escape of crop material from the bale chamber and effecting positive drive to the bale to maintain rotation thereof. This shortcoming applies to both the baler disclosed in U.S. Pat. No. 4,566,379 and in the co-pending apolication referred to.
It is the object of the present invention to overcome the shortcomings of this known machine while taking advantage of the basically satisfactory general type of bale-forming means employed therein.